I designed a circuit with and Arduino Pro Micro (5V), and 2xADNS3050 (optical mouse sensors, 3.3V) and a bunch of other stuff. Now I am trying to optimize the circuit, to free up an extra pin as well as use one 4-channel-3.3v-to-5v-logical-level-shifter less. To do this I bundled the Motion pins of the ADNS3050 and connected these, as well as MISO, directly to the Arduino, as is visible in the image below:

My first question is, Is it OK to attach the MISO from 3.3v to 5v directly without damaging the 3.3v source? My understanding is that since the ADNS3050 is the Slave and MISO stands for "Master In Slave Out", the Slave sets 3.3v to the connection, which is still fine for the Arduino. Are there any negative aspects to doing this, if it is possible?
Secondly, the Motion Pins from the ADNS3050s act as an Interrupt (they go to pin 7 on the Arduino, which is the only leftover interrupt pin that I have) Would bundling them cause any issues? My guess is the same as for MISO as to why these are directly connectable to the 5v Arduino, but if this is not the case I would welcome a heads up.
I do also have a coding question, but Ill dump that elsewhere.
Thanks.